U.S. patent application number 10/528538 was filed with the patent office on 2006-07-06 for cold formed differential housing with integrated ring gear.
Invention is credited to Jianwen Li, Alan Lindsay.
Application Number | 20060143917 10/528538 |
Document ID | / |
Family ID | 32043369 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060143917 |
Kind Code |
A1 |
Lindsay; Alan ; et
al. |
July 6, 2006 |
Cold formed differential housing with integrated ring gear
Abstract
A method for making a differential housing having a ring gear
integrally formed therein includes the steps of providing a
differential housing having an annular rim integrally preformed
therein; supporting the differential housing between upper and
lower halves of a rotatable holding tool such that the annular rim
extends radially outwardly from the holding tool for movement
therewith; providing a thickening tool having a tool surface
engagable with the annular rim during rotation of the holding tool
to form a thickened lip; and providing a gear forming tool
engagable with the thickened lip during rotation of the holding
tool, whereby a plurality of teeth are formed along the lip to form
the ring gear.
Inventors: |
Lindsay; Alan; (Scarborough,
CA) ; Li; Jianwen; (Mississauga, CA) |
Correspondence
Address: |
Robin W Asher;Clark Hill
Suite 3500
500 Woodward Avenue
Detroit
MI
48226-3435
US
|
Family ID: |
32043369 |
Appl. No.: |
10/528538 |
Filed: |
September 29, 2003 |
PCT Filed: |
September 29, 2003 |
PCT NO: |
PCT/CA03/01486 |
371 Date: |
August 24, 2005 |
Current U.S.
Class: |
29/893.34 ;
475/248 |
Current CPC
Class: |
F16H 48/40 20130101;
Y10T 29/49471 20150115; B21K 21/06 20130101; B21D 53/28 20130101;
Y10T 29/49995 20150115; Y10T 29/49464 20150115; Y10T 29/49474
20150115; F16H 2048/382 20130101; B21K 1/26 20130101; B21K 1/30
20130101; Y10T 29/49462 20150115; F16H 48/08 20130101; Y10T
29/49465 20150115 |
Class at
Publication: |
029/893.34 ;
475/248 |
International
Class: |
B21K 1/30 20060101
B21K001/30 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2002 |
US |
60414233 |
Claims
1. A method of making a differential housing having a ring gear
integrally formed therein, said method comprising the steps of:
providing a housing blank having an annular rim; supporting the
housing blank in a rotatable holding tool so that the annular rim
extends radially outwardly from the holding tool for rotation
therewith; rotating the holding tool; and applying a gear forming
tool for engaging the lip during rotation of the holding tool,
whereby a plurality of teeth are formed along the lip to form the
ring gear.
2. The method of making a differential housing of claim 1 further
including the step of applying a first thickening tool for engaging
the annular rim during rotation of the holding tool wherein the
annular rim is plastically deformed to form a lip.
3. The method of making a differential housing of claim 2 wherein
the thickening tool rotates in an opposite direction relative to
the holding tool.
4. The method of making a differential housing of claim 2 further
including applying additional thickening tools to plastically
deform the annular rim to a desired lip dimension.
5. The method of making a differential housing of claim 2 wherein
the first thickening tool is displaced towards the holding tool for
deforming the annular rim.
6. The method of making a differential housing of claim 1 wherein
the annular rim is preformed prior to providing the housing
blank.
7. The method of making a differential housing of claim 1 further
including the step of flow forming the housing blank to form the
annular rim prior to supporting the housing blank in the rotatable
holding tool.
8. The method of making a differential housing of claim 7 wherein
the flow forming step comprises the steps of: providing lower and
upper dies having pre-shaped surfaces, the upper die moveable
relative to the lower die; introducing the housing blank onto the
lower die and moving the upper die to compress the blank within a
cavity defined by the upper and lower die pre-shaped surfaces
wherein an annular rim is formed.
9. The method of making a differential housing of claim 1 wherein
the gear forming tool is rotating in an opposite direction relative
to the holding tool.
10. The method of making a differential housing of claim 1 wherein
the gear forming tool is displaced towards the holding tool for
forming the plurality of teeth.
11. The method of making a differential housing of claim 2 wherein
first and second rotatable holding tools are utilized successively
to hold the housing blank for the step of applying the thickening
tool and the step of applying the gear forming tool.
12. The method of making a differential housing of claim 1 further
including the step of removing material from the lip prior to the
step of applying the gear forming tool.
13. A differential housing comprising: a bell shaped body extending
between a cylindrical first end and an opposing annular second end;
a ring gear integrally formed in the opposing annular second
end.
14. The differential housing as defined in claim 13 wherein the
ring gear extends radially beyond the opposing annular second
end.
15. The differential housing as defined in claim 14 wherein the
ring gear has a predetermined shape.
16. The differential housing as defined in claim 15 wherein the
ring gear comprises a plurality of teeth.
17. The differential housing as defined in claim 15 wherein the
annular second end is plastically deformable for allowing the
annular second end to attain the predetermined shape.
Description
FIELD OF THE INVENTION
[0001] The invention relates to transaxles for an automotive
vehicle, and more particularly, to a differential housing with an
integrated ring gear and a method of forming the housing with the
ring gear integrated therewith.
DESCRIPTION OF THE RELATED ART
[0002] Differential mechanisms are widely used in drive axles in
automobiles for transmitting torque from an engine driven
transmission output to left and right axle shafts. Wheels are
typically secured to the ends of the axle shafts. The differential
mechanism typically includes a plurality of gears for allowing the
left and right axle shafts to rotate at different speeds while
still transmitting torque to the wheels driven by the axle
shafts.
[0003] Conventional differential mechanisms include an outer
housing and a separate ring gear fixedly secured to the outer
housing. Producing separate housings and rings gears and later
interconnecting the ring gears to the housings requires numerous
machining and welding operations. Further, the heat generated
during the welding operations tends to distort the housing and the
ring gear.
[0004] Accordingly, it remains desirable to have a method of
forming a differential housing having a ring gear integrally formed
therein without the need to weld separate a housing and a ring
gear.
SUMMARY OF THE INVENTION
[0005] According to one aspect of the invention, a method of making
a differential housing having a ring gear integrally formed therein
is provided. The method includes the steps of providing a housing
blank having an annular rim integrally preformed therein;
supporting the housing blank in a rotatable holding tool so that
the annular rim extends radially outwardly from the holding tool
for rotation therewith; rotating the holding tool; providing a
thickening tool for engaging the annular rim during rotation of the
holding tool, whereby the annular rim is plastically deformed to
form a lip; and providing a gear forming tool for engaging the lip
during rotation of the holding tool, whereby a plurality of teeth
are formed along the lip to form the ring gear. Also disclosed is a
differential housing having an integrally formed ring gear.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Advantages of the present invention will be readily
appreciated as the same becomes better understood by reference to
the following detailed description when considered in connection
with the accompanying drawings wherein:
[0007] FIG. 1 is a perspective view of a differential assembly
according to one aspect of the invention;
[0008] FIG. 2 is a cross sectional view of a die tool and housing
blank formed in the die tool according to one aspect of the
invention;
[0009] FIG. 3 is a cross sectional view of a holding tool and a
thickening tool for forming a thickened lip in the housing
blank;
[0010] FIG. 4 is a cross sectional view of the holding tool and a
second thickening tool;
[0011] FIG. 5 is a cross sectional view of the holding tool and a
gear forming tool for forming the ring gear from the thickened
lip;
[0012] FIG. 6 is a cross sectional view of the die tool according
to a second embodiment of the invention; and
[0013] FIG. 7 is a cross sectional view of the die tool according
to a third embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Referring to the figures, a differential assembly for a
transaxle in an automotive vehicle is generally indicated at 10 in
FIG. 1. The differential assembly 10 includes a plurality of pinion
gears 12 matingly engaged, as known by those of ordinary skill in
the art, for transmitting torque from a transmission output (not
shown) to left and right axle shafts and for allowing the left and
right axle shafts to rotate at different speeds. The pinion gears
are operatively supported by a differential housing 20. The housing
20 includes a generally bell shaped body 22 extending between a
generally cylindrical first end 24 and an opposite annular second
end 26. A ring gear 30 is integrally formed in the second end 26 of
the housing 20. A method of integrally forming the ring gear 30
into the second end 26 of the housing is described in detail
below.
[0015] Referring to FIG. 2, a mandrel or lower die 40 is provided
having a pre-shaped, positive lower tool surface 42. An upper die
50 is provided having a pre-shaped upper tool surface 52. The upper
tool surface 52 is generally complementary to the lower tool
surface 42. The upper die 50 is forcibly movable relative to the
lower die 40 between an open position, as shown in FIG. 2, and a
closed position against the lower die 40, by any suitable means,
such as a hydraulic press assembly. In the closed position, a
cavity 58 is defined between the tool surfaces 42, 52 of the lower
40 and upper 50 dies that generally define the desired shape of the
housing 20. In the open position, the lower die 40 is exposed to
allow the placement or removal of a housing blank 60.
[0016] While the upper die 50 is in the open position, a pre-formed
housing blank 60 is placed onto the lower tool surface 42. The
upper die 50 is forcibly moved to the closed position, whereby the
housing blank 60 is compressed between the lower 42 and upper 52
tool surfaces. The housing blank 60 is flow or cold formed to
retain the general shape of the cavity 58. An annular rim 62 is
formed in the housing blank 60 defining a rim axis 61.
[0017] Referring to FIGS. 3 and 4, a first holding tool 70 having a
generally cylindrical outer peripheral surface 71 is provided. The
first holding tool 70 includes upper 72 and lower 74 holding
members. The first holding tool 70 is rotatably supported by
external support means (not shown) for rotation about a first
rotary axis 75. The upper 72 and lower 74 holding members have
complementary upper 76 and lower 78 clamping surfaces,
respectively, adapted for nestingly supporting the housing blank 60
therebetween. The upper 76 and lower 78 clamping surfaces each
extend between the outer peripheral surface 71. The housing blank
60 is placed into and clamped between the upper 76 and lower 78
clamping surfaces such that the rim axis 61 is aligned with the
first rotary axis 75 and the rim 62 protrudes radially beyond the
outer peripheral surface 71.
[0018] A thickening tool 80 having a forming surface 82 for
plastically deforming the rim 62 is provided and rotatably
supported by external support means (not shown) for rotation about
a second rotary axis 83.
[0019] The first holding tool 70 and thickening tool 80 are rotated
in opposite directions about their respective first 75 and second
83 rotary axes by any suitable means, such as an electric motor, at
preselected fixed or variable speeds. The housing blank 60, clamped
between the upper 76 and lower 78 clamping surfaces, rotates with
the holding tool 70. The thickening tool 80 is displaced toward the
first holding tool 70 by any suitable means, such as a hydraulic
cylinder, so that the forming surface 82 frictionally engages the
rim 62. The forming surface 82 is forcibly held against the rim 62
until the outer periphery of the rim 62 is plastically deformed
into a thickened or bulbuous annular lip 84, as shown in FIG. 3.
The forming surface 82 may be held against the rim 62 continuously
in a single pass or in successive passes until a desired shape of
the lip 84 is achieved. Second 88 or third (not shown) thickening
tools may be utilized in succession until the desired shape of the
lip 84 is achieved, as shown in FIG. 4. The housing blank 60 is
removed from between the upper 76 and lower 78 clamping
surfaces.
[0020] Referring to FIG. 5, a second holding tool 90 having a
generally cylindrical outer peripheral surface 91 is provided. The
second holding tool 90 includes upper 92 and lower 94 holding
members. The second holding tool 90 is rotatably supported by
external support means (not shown( for rotation about a third
rotary axis 95. The upper 92 and lower 94 holding members have
complementary upper 96 and lower 98 clamping surfaces, respectively
adapted for nestingly supporting the housing blank 60 therebetween.
The upper 96 and lower 98 clamping surfaces each extend between the
outer peripheral surface 91 of the second holding tool 90. The
housing blank 60 is placed into and clamped between the upper 96
and lower 98 clamping surfaces such that the rim axis 61 is aligned
with the third rotary axis 95 and the bulbuous lip 84 protrudes
radially beyond the outer peripheral surface 91.
[0021] A gear forming tool 100 having a gear forming surface 102
for forming the teeth of the rim gear 30 is provided and rotatably
supported by external support means (not shown) for rotation about
a fourth rotary axis 104.
[0022] The second holding tool 90 and the gear forming tool 100 are
rotated in opposite directions about their respective third 95 and
fourth 104 rotary axes by any suitable means, such as an electric
motor, at preselected fixed or variable speeds. The housing blank
60, clamped between the upper 96 and lower 98 clamping surfaces,
rotates with the second holding tool 90. The gear forming tool 100
is displaced toward the second holding tool 90 by any suitable
means, such as a hydraulic cylinder, so that the gear forming
surface 102 frictionally engages the lip 84. The gear forming
surface 102 is forcibly held against the lip 84. The gear forming
surface 102 cuts and plastically deforms the lip 84 to form the
teeth of the rim gear 30. The gear forming surface 102 may be
applied to the lip 84 in successive steps until a final desired
shape for the teeth of the rim gear 30 is achieved. Thus, a rim
gear 30 is integrally formed in the housing 20 without welding and
with minimal material loss.
[0023] An alternative method of integrally forming the rim gear 30
in the housing 20 is shown in FIG. 6. The upper die 150 is forcibly
moved to the closed position, whereby the housing blank 160 is
compressed between the lower 142 and upper 152 tool surfaces of the
lower 140 and upper 150 dies. The housing blank 160 is flow or cold
formed to retain the general shape of the cavity 158 formed between
the lower 142 and upper 152 tool surfaces in the closed position. A
thickened lip 184 is formed in the housing blank 160 without the
intermediate steps of utilizing successive thickening tools. The
rim gear 30 is cut and formed from the thickened lip 184, as
discussed.
[0024] As best shown in FIG. 7 excess material 185 may be
subsequently removed from the thickened lip 184 prior to forming
the teeth of the rim gear 30 to achieve a desired shape of the lip
184 not possible with flow or cold forming alone.
[0025] The invention has been described in an illustrative manner,
and it is to be understood that the terminology, which has been
used, is intended to be in the nature of words of description
rather than of limitation.
[0026] Many modification and variations of the present invention
are possible in light of the above teachings. It is, therefore, to
be understood that within the scope of the appended claims, the
invention may be practiced other than as specifically
described.
* * * * *